Aircraft equipment problem -- APU smoke.

Attributes
ACN	303786
Time
Date	199505
Day	Sat
Local Time Of Day	0601 To 1200
Place
Locale Reference	airport : sea
State Reference	WA
Altitude	agl bound lower : 0 agl bound upper : 0
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	Commercial Fixed Wing
Operating Under FAR Part	Part 121
Navigation In Use	Other
Flight Phase	ground : preflight other
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : commercial pilot : flight engineer pilot : instrument
Experience	flight time last 90 days : 180 flight time total : 18000 flight time type : 11000
ASRS Report	303786
Person 2
Affiliation	company : air carrier
Function	flight crew : second officer
Qualification	pilot : instrument pilot : commercial
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	aircraft equipment other aircraft equipment : unspecified other other : unspecified
Resolutory Action	none taken : anomaly accepted other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Shortly after arrival at aircraft, so started APU, and put it on line (electric and pneumatic/packs). While he was working on fuel slip -- about 30 seconds later -- a ramp person ran onto plane -- came to cockpit and reported smoke coming from APU. Just about same time APU automatic-shut down and cabin filled with heavy,acrid smoke. Ground service personnel called seatac fire/emergency crews and they stood by briefly. I was at podium area doing flight plan and release etc, and returning to the aircraft became aware of problem. Aft cabin, especially zones C and D had especially heavy smoke, depth 4-5 ft from the floor. It was very difficult to see floor. No passenger were on board opened doors to ventilate but it took a long time -- no conditioned air truck was available. Smoke penetrated fabric and coated surfaces -- even when cleared out and air-conditioning system had been purged. Aircraft atmosphere remained very irritating to eyes and lungs 3 hours later. Smoke would surely have caused a panic situation if passenger had been on aircraft. Scheduled flight eventually canceled. Cause of APU failure unknown.

Original NASA ASRS Text

Title: ACFT EQUIP PROB -- APU SMOKE.

Narrative: SHORTLY AFTER ARR AT ACFT, SO STARTED APU, AND PUT IT ON LINE (ELECTRIC AND PNEUMATIC/PACKS). WHILE HE WAS WORKING ON FUEL SLIP -- ABOUT 30 SECONDS LATER -- A RAMP PERSON RAN ONTO PLANE -- CAME TO COCKPIT AND RPTED SMOKE COMING FROM APU. JUST ABOUT SAME TIME APU AUTO-SHUT DOWN AND CABIN FILLED WITH HVY,ACRID SMOKE. GND SVC PERSONNEL CALLED SEATAC FIRE/EMER CREWS AND THEY STOOD BY BRIEFLY. I WAS AT PODIUM AREA DOING FLT PLAN AND RELEASE ETC, AND RETURNING TO THE ACFT BECAME AWARE OF PROB. AFT CABIN, ESPECIALLY ZONES C AND D HAD ESPECIALLY HVY SMOKE, DEPTH 4-5 FT FROM THE FLOOR. IT WAS VERY DIFFICULT TO SEE FLOOR. NO PAX WERE ON BOARD OPENED DOORS TO VENTILATE BUT IT TOOK A LONG TIME -- NO CONDITIONED AIR TRUCK WAS AVAILABLE. SMOKE PENETRATED FABRIC AND COATED SURFACES -- EVEN WHEN CLRED OUT AND AIR-CONDITIONING SYS HAD BEEN PURGED. ACFT ATMOSPHERE REMAINED VERY IRRITATING TO EYES AND LUNGS 3 HRS LATER. SMOKE WOULD SURELY HAVE CAUSED A PANIC SIT IF PAX HAD BEEN ON ACFT. SCHEDULED FLT EVENTUALLY CANCELED. CAUSE OF APU FAILURE UNKNOWN.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.